"OSError: [WinError 126] The specified module could not be found" when trying to import strym on windows machine

[iejones]

I am working with windows on Anaconda. As suggested on the Conda website, I made an enviroment and installed the other packages I wanted with conda before installing strym with pip (https://docs.conda.io/projects/conda/en/latest/user-guide/tasks/manage-environments.html#using-pip-in-an-environment). Strym appears to have installed properly and Anaconda Navigator shows that I have it installed. When I try to import styrm I receive this error message:

OSError                                   Traceback (most recent call last)
<ipython-input-4-f6f98c63973a> in <module>
----> 1 import strym
D:\GamesAndPrograms\Anaconda3\envs\copyCat\lib\site-packages\strym\__init__.py in <module>
----> 1 from .strym import strym
      2 from .strym import __version__
      3 from .strym import __author__
      4 from .strym import __email__
      5 from .strymread import *
D:\GamesAndPrograms\Anaconda3\envs\copyCat\lib\site-packages\strym\strym.py in <module>
     63 from os.path import expanduser
     64 
---> 65 import libusb1
     66 import usb1
     67 
D:\GamesAndPrograms\Anaconda3\envs\copyCat\lib\site-packages\libusb1.py in <module>
      6 )
      7 del warnings
----> 8 from usb1.libusb1 import *
D:\GamesAndPrograms\Anaconda3\envs\copyCat\lib\site-packages\usb1\__init__.py in <module>
     59 import contextlib
     60 import inspect
---> 61 from . import libusb1
     62 if sys.version_info[:2] >= (2, 6):
     63 # pylint: disable=wrong-import-order,ungrouped-imports
D:\GamesAndPrograms\Anaconda3\envs\copyCat\lib\site-packages\usb1\libusb1.py in <module>
    190         return dll_loader(libusb_path, **loader_kw)
    191 
--> 192 libusb = _loadLibrary()
    193 
    194 # libusb.h
D:\GamesAndPrograms\Anaconda3\envs\copyCat\lib\site-packages\usb1\libusb1.py in _loadLibrary()
    164         loader_kw['use_last_error'] = True
    165     try:
--> 166         return dll_loader('libusb-1.0' + suffix, **loader_kw)
    167     except OSError:
    168         libusb_path = None
D:\GamesAndPrograms\Anaconda3\envs\copyCat\lib\ctypes\__init__.py in __init__(self, name, mode, handle, use_errno, use_last_error)
    362 
    363         if handle is None:
--> 364             self._handle = _dlopen(self._name, mode)
    365         else:
    366             self._handle = handle
OSError: [WinError 126] The specified module could not be found

[iejones]

I found a solution. In accordance with this line of the error message, --> 166 return dll_loader('libusb-1.0' + suffix, **loader_kw), I could not find libusb-1.0.dll in my environment directory. These steps fixed it:

1. Downloaded the binary snapshots for libusb-1.0 for windows here or here
2. Extract it with 7-zip
3. Copy libusb-1.0.dll into the folder in the directory with phython.exe

For me, that folder was my environment folder, D:\GamesAndPrograms\Anaconda3\envs\copycat
Now, import strym does not produce the error.
I also used these pages to find this solution: https://github.com/libusb/libusb/wiki/Windows and trezor/python-trezor#218